Disposable absorbent articles, such as diapers, training pants, incontinence garments and the like, have typically employed adhesive tape tabs to secure the absorbent article about the waist of the wearer. It has been desirable to have adhesive tape tabs which are capable of being fastened and refastened several times. The refastenability of the tape tabs permits an adjustment of the fit on the wearer, and allows a selected unfastening and opening of the article for inspection. If the article is suitable for continued use, the adhesive tabs can then be refastened to again secure the garment on the wearer.
Particular disposable diaper designs have employed a film of reinforcing material secured to the outer surface of the garment cover layer to prevent tearing of the cover layer when an adhesive tape tab is peeled away. For example, U. K. Patent No. GB 2 129 689 B published 22 Oct. 1986 with the inventor listed as L. Widlund describes a disposable diaper having a thin plastic outer layer reinforced with plastic strips to allow a removal and refastening of adhesive tape fasteners. Similarly, European Patent Application No. EP 0 080 647 A1 published 8 June 1983 with the inventors listed as R. deJonckheere, et al. describes a disposable diaper having a plastic outer sheet reinforced by one or more strips to improve the tensile strength of the outer sheet in the regions where adhesive tape fasteners are applied. The reinforcing strips permit the adhesive tabs to be opened and reclosed several times without rendering the article unserviceable. The documents discussed above, however, do not disclose any method or apparatus for manufacturing the diapers with the reinforcement patch.
U.S. Pat No. 2,289,336 to A. Bamford describes a method and apparatus for applying windows of transparent material to a moving base material. The apparatus employs a rotary suction carrier which moves portions of sheet material into an applying zone at a constant rate of continuous travel. A mechanism displaces individual suction elements outwardly and substantially radially of the suction carrier to apply individual portions of sheet material to the base material.
Another technique for applying window patches to a moving web is described in U.S. Pat. No. 4,642,085 issued Feb. 10, 1987 to H. Helm. An apparatus described by Helm feeds a web of patch material to an adhesive applying mechanism. A vacuum conveyor transports the web from the adhesive applying mechanism to a severing mechanism which cuts successive window patches from a preselected length of the web in spaced relation to a portion of the web engaged on the surface of a vacuum roll. The vacuum roll then applies the patches to a moving base sheet layer.
Other techniques for applying patches to a moving web are described in U.S. Pat. No. 2,958,437 issued Nov. 1, 1960 to A. Mengis; U.S. Pat. No. 4,061,527 issued Dec. 6, 1977 to J. Traise; U.S. Pat. No. 3,933,564 issued Jan. 20, 1976 to O. Jensen; and U.S. Pat. No. 4,475,969 issued Oct. 9, 1984 to C. Reed.
In addition, various other devices have been developed to apply reinforcing strips onto selected base sheets. For example, see U.S. Pat. No. 3,616,027 issued Oct. 26, 1971 to K. Honsel; U.S. Pat. No. 3,850,724 issued Nov. 26, 1974 to H. Lehmacher; and U.S. Pat. No. 3,012,481 issued Dec. 12, 1961 to W. Hughes.
Conventional devices, such as those described above, have not been able to provide an in-line process which adequately regulates and controls the steps of applying a selected coating of adhesive onto a film substrate, separating the coated substrate into separate individual patches, and applying the patches to spaced-apart regions of a moving web layer. As a result, conventional techniques have not been adequate for tasks such as applying reinforcement patches to the outer covers of disposable absorbent garments. The techniques have generated excessive waste and have required excessive maintenance.